src/main/java/org/apache/log4j/rule/AndRule.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.log4j.rule;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.Stack;
import org.apache.log4j.chainsaw.logevents.ChainsawLoggingEvent;

/**
 * A Rule class implementing a logical 'and'.
 *
 * @author Scott Deboy (sdeboy@apache.org)
 */
public class AndRule extends AbstractRule {
    /**
     * First rule.
     */
    private final Rule firstRule;
    /**
     * Second rule.
     */
    private final Rule secondRule;
    /**
     * Serialization id.
     */
    static final long serialVersionUID = -8233444426923854651L;

    /**
     * Create new instance.
     * @param first first rule.
     * @param second second rule.
     */
    private AndRule(final Rule first, final Rule second) {
        super();
        this.firstRule = first;
        this.secondRule = second;
    }

    /**
     * Create rule from top two elements of stack.
     * @param stack stack of rules.
     * @return Rule that evaluates true only if both rules are true.
     */
    public static Rule getRule(final Stack stack) {
        if (stack.size() < 2) {
            throw new IllegalArgumentException("Invalid AND rule - expected two rules but received " + stack.size());
        }
        Object o2 = stack.pop();
        Object o1 = stack.pop();
        if ((o2 instanceof Rule) && (o1 instanceof Rule)) {
            Rule p2 = (Rule) o2;
            Rule p1 = (Rule) o1;
            return new AndRule(p1, p2);
        }
        throw new IllegalArgumentException("Invalid AND rule: " + o2 + "..." + o1);
    }

    /**
     * Get rule.
     * @param firstParam first rule.
     * @param secondParam second rule.
     * @return Rule that evaluates true only if both rules are true.
     */
    public static Rule getRule(final Rule firstParam, final Rule secondParam) {
        return new AndRule(firstParam, secondParam);
    }

    /**
     * {@inheritDoc}
     */
    public boolean evaluate(final ChainsawLoggingEvent event, Map matches) {
        if (matches == null) {
            return firstRule.evaluate(event, null) && secondRule.evaluate(event, null);
        }
        Map tempMatches1 = new HashMap();
        Map tempMatches2 = new HashMap();
        boolean result = firstRule.evaluate(event, tempMatches1) && secondRule.evaluate(event, tempMatches2);
        if (result) {
            for (Iterator iter = tempMatches1.entrySet().iterator(); iter.hasNext(); ) {
                Map.Entry entry = (Map.Entry) iter.next();
                Object key = entry.getKey();
                Set value = (Set) entry.getValue();
                Set mainSet = (Set) matches.get(key);
                if (mainSet == null) {
                    mainSet = new HashSet();
                    matches.put(key, mainSet);
                }
                mainSet.addAll(value);
            }
            for (Iterator iter = tempMatches2.entrySet().iterator(); iter.hasNext(); ) {
                Map.Entry entry = (Map.Entry) iter.next();
                Object key = entry.getKey();
                Set value = (Set) entry.getValue();
                Set mainSet = (Set) matches.get(key);
                if (mainSet == null) {
                    mainSet = new HashSet();
                    matches.put(key, mainSet);
                }
                mainSet.addAll(value);
            }
        }
        return result;
    }
}